Title: A few tips about the cd command
       Author: Solène
       Date: 04 September 2020
       Tags: unix
       Description: 
       
       While everyone familiar with a shell know about the command `cd`
       there are a few tips you should know.
       
       ### Moving to your $HOME directory
       
           $ pwd
           /tmp
           $ cd
           $ pwd
           /home/solene
       
       Using `cd` without argument will change your current directory to
       your $HOME.
       
       
       ### Moving into someone $HOME directory
       
       While this should fail most of the time because people shouldn't allow
       anyone to visit their $HOME, there are use case it can be used though.
       
           $ cd ~user1
           $ pwd
           /home/user1
           $ cd ~solene
           $ pwd
           /home/solene
       
       Using `~user` as a parameter will move to that user $HOME directory,
       note that `cd` and `cd ~youruser` have the same result.
       
       
       ### Moving to previous directory
       
       This is a very useful command which allow going back and forth between
       two directories.
       
           $ pwd
           /home/solene
           $ cd /tmp
           $ pwd
           /tmp
           $ cd -
           /home/solene
           $ pwd
           /home/solene
       
       When you use `cd -` the command will move to the previous directory
       in which you were. There are two special variables in your shell:
       `PWD` and `OLDPWD`, when you move somewhere, `OLDPWD` will hold
       your current location before moving and then `PWD` hold the new
       path. When you use `cd -` the two variables get exchanged, this
       mean you can only jump from two paths using `cd -` multiple times.
       
       Please note that when using `cd -` your new location is displayed.
       
       
       ### Changing directory by modifying current PWD
       
       thfr@ showed me a cd feature I never heard about, and it's the
       perfect place to write about it. Note that this work in ksh and zsh
       but is reported to not work in bash.
       
       One example will explain better than any text.
       
           $ pwd
           /tmp/pobj/foobar-1.2.0/work
           $ cd 1.2.0 2.4.0
           /tmp/pobj/foobar-2.4.0/work
       
       This tells `cd` to replace first parameter pattern by the second
       parameter in the current `PWD` and then cd into it.
       
           $ pwd
           /home/solene
           $ cd solene user1
           /home/user1
       
       This could be done in a bloated way with the following command:
       
           $ cd $(echo $PWD | sed "s/solene/user1/")
       
       I learned it a few minutes ago but I see a lot of uses cases where
       I could use it.
       
       
       ### Moving into the current directory after removal
       
       In some specific case, like having your shell into a directory that
       existed but was deleted and removed (this happens often when you
       working into compilation directories).
       
       A simple trick is to tell `cd` to go to the current location.
       
           $ cd .
       
       or
       
           $ cd $PWD
       
       And `cd` will go into the same path and you can start hacking
       again in that directory.